One or more example embodiments relate to a common-path optical fiber based handheld parallel optical coherence tomography (OCT) apparatus.
In a medical field, an optical coherence tomography (OCT) has been used to acquire a tomographic image of a measurement target. The OCT is technology for acquiring a high resolution tomographic image by radiating an infrared ray to the measurement target and analyzing a reaching time and an amount of light reflected from the measurement target based on a property of tissue using an optical interferometer. In contrast to ultrasonic waves, light may not deeply penetrate a living tissue due to scattering and absorption. Thus, the light may be applied through a fiber-optic endoscope to acquire an inner body image.
The OCT may be classified in the view of beam scanning type into a single point scanning and a parallel scanning for acquiring two-dimensional and three-dimensional information. Although research on the parallel type is actively conducted based on advantageous effects such as a quick acquirement of an image, the parallel type may be restrictively applicable to, for example, endoscope because parallel optical data is not transmittable to an optical fiber.
In related arts, a parallel OCT apparatus may include an inspection lens configured to radiate a near infrared ray to a measurement target and detect a light reflected from the measurement target, and a mirror configured to output a reference light used for a light interference. Also, the parallel OCT apparatus may adopt a two-arm type to perform the light interference on the reference light and the reflected light from the measurement target, both of which are transmitted through two stationary paths.
When an interferometer of the conventional parallel OCT apparatus is manufactured using an optical fiber, the inspection lens, the mirror, and optical fiber cables may be connected to one another to transfer the light. In this example, when a posture of at least one of the optical fiber cables is changed or when at least one of the optical fiber cables is wobbled, noise may occur due to a change in phase difference of the reference light and the reflected light in a process of performing the light interference. For this reason, in a process of capturing an image, the inspection lens and the mirror may need to be fixed without using an optical fiber cable.